CVE-2026-99184: accel/rocket: search every core slot when a core is removed

In the Linux kernel, the following vulnerability has been resolved:

accel/rocket: search every core slot when a core is removed

rocketremove() decrements rdev->numcores for each core it removes, while findcorefordev() searches slots 0 to numcores - 1. Unbinding the cores in the order they were bound therefore loses the last one: by the time it is removed the search range has already shrunk past its slot, so findcorefordev() returns -1 and rocketremove() gives up without doing anything.

numcores never reaches zero, rocketdevicefini() never runs, and the file-scoped rdev keeps pointing at a device that is going away. Binding the cores again starts from that stale count, because rocketprobe() takes rdev->numcores as the slot to fill. On an RK3588, which describes three cores, the second round lands on slots 1, 2 and 3 while rdev->cores was allocated with room for three:

rocket fdab0000.npu: Rockchip NPU core 1 version: 1179210309 rocket fdac0000.npu: Rockchip NPU core 2 version: 1179210309 rocket fdad0000.npu: Rockchip NPU core 3 version: 1179210309

The write to rdev->cores[3] is past the end of the array.

Nothing in tree reads the core array often enough to notice, so the overrun is silent today. It turned up while testing a devfreq series on top of this, where a worker walks every core a few times a second, and UBSAN caught the first bool it read out of the overrun entry:

UBSAN: invalid-load in drivers/accel/rocket/rocketdevfreq.c:47:10 load of value 5 is not a valid value for type 'Bool' Workqueue: devfreqwq devfreqmonitor

Record how many slots were allocated and search all of them. Every core is then found on removal, numcores reaches zero, the device is torn down and a later bind starts from a clean rdev.

This does not make unbinding a single core out of several work. probe still takes numcores as the slot to fill, so rebinding one core while its siblings stay bound would write over a slot that is already in use, and rocketopen() still reaches for cores[0] whether or not anything is there. Both of those want more thought than a fix should carry.

Found by unbinding and rebinding all three cores on an Orange Pi 5 Plus. With this applied, 25 unbind/rebind rounds and 5 module unload/reload rounds run clean there: the cores land in slots 0, 1 and 2 every time, whichever order they are bound in, and the shared supply goes back to a single user after each round.